# length extension attack

> attack against cryptographical hash functions, where knowing Hash(message₁) and the length of message₁ allows an attacker to calculate Hash(message₁ ‖ message₂) for an attacker-controlled message₂

**Wikidata**: [Q6522491](https://www.wikidata.org/wiki/Q6522491)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Length_extension_attack)  
**Source**: https://4ort.xyz/entity/length-extension-attack